The present invention generally relates to a fluid treatment element and fluid treatment methods such as filtering and material transfer from one fluid to another, and particularly to a filter element defining a flow path for process fluid passing in a lengthwise direction of the fluid treatment element.
In one conventional type of fluid treatment known as dead end treatment, a fluid to be treated is introduced into a fluid treatment element, and the entirety or substantially all of the fluid is passed through a fluid treatment medium of the fluid treatment element to be filtered or otherwise treated. In another conventional type of fluid treatment known as crossflow filtration, a fluid to be treated is introduced into a fluid treatment element and is made to flow along the surface of a fluid treatment medium of the fluid treatment element. This flow of fluid along the surface is usually referred to as crossflow. Only a portion of the fluid passes through the fluid treatment medium to be filtered or otherwise treated, while the remainder of the fluid is discharged from the fluid treatment element without passing through the fluid treatment medium.
The fluid which is introduced into the element for treatment is usually referred to as process fluid, the fluid which passes through the fluid treatment medium is usually referred to as permeate, while the fluid which is discharged from the fluid treatment element without passing the fluid treatment medium is usually referred to as retentate. The crossflow of fluid along the surface of the fluid treatment medium generates a fluid shear force in the fluid adjoining the fluid treatment medium which slows the rate at which particles accumulate on the fluid treatment medium.
Each of these types of fluid treatment methods has advantages and disadvantages. In certain crossflow treatment or filtration, since particles accumulate on the surface of a fluid treatment medium more slowly than in dead end treatment, a fluid treatment element operated in a crossbow mode will typically have a longer useful life before requiring cleaning or replacement than a fluid treatment operated in the dead end mode. On the other hand, a fluid treatment element operated in crossflow mode requires greater volumes of fluid than does a fluid treatment element operated in dead end mode, since much of the fluid introduced into the fluid treatment element exits from it as retentate.
Furthermore, a crossflow fluid treatment element may require higher flow velocities than a dead end fluid treatment element, since a certain crossflow velocity is necessary to produce an adequate fluid shear force to prevent the accumulation of particles on the fluid treatment medium. For these reasons, a fluid treatment system employing a crossflow fluid treatment element is usually more complicated than one employing a dead end fluid treatment element and may be unsuitable for situations in which it is desired to treat small volumes of fluid at low flow rates.
The foregoing shows that there exists a need for a fluid treatment element that is capable of providing the advantages of crossflow as well as dead end treatment modes. There further exists a need for a method of cleaning fluid treatment elements such as filter elements which become loaded with particles during fluid treatment.
Furthermore, in the treatment of fluids, for example, in the dissolution of or removal of gases in liquids, certain problems are encountered. For example, in a conventional method of dissolving gases such as by bubbling a gas into a liquid, the resulting solution contains tiny gas bubbles. Such solutions are unfit for certain applications that require stringent purity, for example, in the manufacturing of semiconductors. The fluids considered for cleaning of the silicon wafer, particularly corrosive or active fluids such as ozonated water, ozonated sulfuric acid, or aqueous solutions of hydrofluoric acid, when prepared by conventional methods contain bubbles that may adhere to the wafer and adversely affecting the quality or performance of the semiconductor. Further, such conventional methods, as they operate on a sparging mode, provide rather low or inefficient gas to liquid transfer or dissolution rates.
Thus, there exists a need for a system or arrangement for treatment of fluids, for example, dissolution of or removal of gases in liquids. There further exists a need for fluid treatment elements which are resistant to corrosive fluids. There further exists a need for fluid treatment elements that do not degrade or release contaminants into the process fluids. Thus, there exists a need for fluid treatment elements that are free or substantially free of extractables.
These and other advantages of the present invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.
The present invention provides a fluid treatment element capable of operation in a crossflow mode. The present invention also provides a fluid treatment element having a large surface area available for fluid treatment. The present invention further provides a fluid treatment element which can have a variety of flow paths through it.
The present invention additional provides a fluid treatment element suitlable for crossflow fluid treatment which can be connected in series with one or more additional fluid treatment elements without a large decrease in the energy of a fluid performing crossflow. The present invention also provides a treatment element which can be cleaned by crossflow. additionally provides methods of cleaning a fluid treatment element by crossflow.
Fluid treatment elements may comprise a fluid treatment pack having first and second lengthwise end faces and including a fluid treatment layer having first and second sides and a sealing strip extending for less than a length of the fluid treatment pack on the first side of the fluid treatment layer and preventing fluid from flowing through the first lengthwise end face into the fluid treatment pack on the first side of the fluid treatment layer.
Fluid treatment elements may comprise a hollow fluid treatment pack containing a fluid treatment medium and a core surrounded by the fluid treatment pack and having a blind region in which fluid cannot flow between an interior of the core and the fluid treatment pack extending continuously over at least fifty percent of a length of the fluid treatment pack.
Fluid treatment elements adapted for cross flow filtration may comprise a fluid treatment pack having a fluid treatment layer, a first mesh layer disposed on a first side of the fluid treatment layer, and a second mesh layer disposed on a second side of the fluid treatment layer, the fluid treatment elements defining a flow path for a process fluid to be treated passing in a lengthwise direction of the fluid treatment element inside the first mesh layer and a flow path for permeate passing through the second mesh layer.
Fluid treatment assemblies may comprise a housing having a process fluid chamber, a permeate chamber, and a retentate chamber, and a cylindrical fluid treatment element disposed in the housing and comprising a pleated fluid treatment layer having a radially inner side and a radially outer side, the fluid treatment element defining a first flow path passing through the fluid treatment element in a lengthwise direction of the fluid treatment element along the radially inner side of the fluid treatment layer between the process fluid chamber and the retentate chamber, and a second flow path passing through the fluid treatment layer between the process fluid chamber and the permeate chamber.
Fluid treatment elements may comprise a fluid treatment pack through which fluid can flow in a lengthwise direction of the fluid treatment pack and surrounding a hollow center of the fluid treatment element, and a flow restriction disposed in the hollow center for partially restricting fluid flow in the lengthwise direction of the fluid treatment element through the hollow center.
Fluid treatment arrangements may comprise a first fluid treatment element having a hollow center and first and second lengthwise ends and including a fluid treatment pack surrounding the hollow center and containing a fluid treatment medium, the first fluid treatment element defining a first flow path between the first and second ends through the fluid treatment pack and a second flow path through the hollow center between the first and second ends and bypassing the fluid treatment pack, and a flow restriction disposed in the hollow center for partially restricting fluid flow in a lengthwise direction of the fluid treatment clement through the hollow center, and a second fluid treatment element connected in series with the first fluid treatment element so as to receive fluid passing along the first and second flow paths of the first fluid treatment element and defining a first flow path passing through a fluid treatment pack of the second fluid treatment element.
Fluid treatment elements include a fluid treatment pack containing a fluid treatment medium and a bypass passage surrounding the fluid treatment pack and enabling fluid to flow in a lengthwise direction of the fluid treatment element while bypassing the fluid treatment pack, the bypass passage having an inlet at a first lengthwise end of the fluid treatment element and an outlet at a second lengthwise end of the fluid treatment element, an interior of the bypass passage being isolated from the fluid treatment pack between the inlet and outlet.
Fluid treatment arrangements may comprise a first fluid treatment element including a fluid treatment pack containing a fluid treatment medium, a first member surrounding the fluid treatment pack, and a second member surrounding the first member and defining a bypass passage between the first and second members through which fluid can flow in a lengthwise direction of the first fluid treatment element while bypassing the fluid treatment pack, and a second fluid treatment element connected in series with the first fluid treatment element so as to receive fluid passing through the fluid treatment pack and the bypass passage of the first fluid treatment element.
Fluid treatment arrangements may comprise a cylindrical fluid treatment element comprises a hydrophobic gas pore membrane having first and second sides, the fluid treatment element defining a first flow path in a lengthwise direction of the fluid treatment element on the first side of the membrane and a second flow path in a lengthwise direction of the fluid treatment element on the second side of the membrane, a ClO2 generator fluidly connected to the first flow path for supplying an aqueous solution containing dissolved ClO2 to the fluid treatment element, and a source of a fluid to receive ClO2 fluidly connected to the second flow path.
Fluid treatment assemblies may comprise a housing which has first through fourth tube sheets and which is divided by the tube sheets in a lengthwise direction of the housing into a first chamber, a second chamber located between the first and second tube sheets and separated from the first chamber by the first tube sheet, a third chamber located between the second and third tube sheets, a fourth chamber located between the third and fourth tube sheets, and a fifth chamber separated from the fourth chamber by the fourth tube sheet, each of the chambers having a fluid port communicating between the chamber and an exterior of the housing, and at least one fluid treatment element disposed in the second chamber and fluidly communicating with the first and third chambers through openings in the fist and second tube sheets, and at least one fluid treatment element disposed in the fourth chamber and fluidly communicating with the third and fifth chambers through openings in the third and fourth tube sheets.
Fluid treatment elements may comprise a fluid treatment pack having axially extending pleats and comprising a pleated composite including a fluid treatment layer, a first drainage layer on a first side of the fluid treatment layer, and a second drainage layer on a second side of the fluid treatment layer, a first open end cap sealed to a first lengthwise end of the fluid treatment pack and a second open end cap sealed to a second lengthwise end of the fluid treatment pack, and a core surrounded by the fluid treatment pack and having first and second open ends, a first perforated region adjoining the first open end of the core and having a blind inner end, and a second perforated region adjoining the second open end of the core and having a blind inner end, fluid being able to flow between the perforated regions only on an exterior of the core.
Fluid treatment elements may comprise a pleated fluid treatment pack containing a fluid treatment layer having a radially inner side and a radially outer side and a hollow center, a first lengthwise end into which a process fluid can flow into the radially outer side of the fluid treatment layer but not into the radially inner side of the fluid treatment layer, and a second lengthwise end having a lengthwise end face which is sealed to prevent fluid from flowing through the lengthwise end face, and a tube surrounding the fluid treatment pack and preventing fluid from flowing in a radial direction of the fluid treatment element between the fluid treatment pack and an exterior of the fluid treatment element except in a region in a vicinity of the second lengthwise end of the fluid treatment pack.
Fluid treatment elements may comprise a hollow pleated fluid treatment pack having two lengthwise end faces through which fluid can flow into the fluid treatment pack, a fluid impervious member surrounding the fluid treatment pack for preventing fluid from flowing into the fluid treatment pack from an exterior of the fluid treatment element between the lengthwise end faces, a sealing member for sealing a first lengthwise end of the fluid treatment element to a tube sheet of a fluid treatment housing, a tube communicating with the hollow center of the fluid treatment pack and extending outwards from one of the lengthwise end faces of the fluid treatment pack, and a sealing member for sealing the tube to a tube sheet of a fluid treatment housing.
Fluid treatment assemblies may comprise a fluid treatment housing including first and second tube sheets, a first chamber adjoining the first tube sheet, a second chamber between the first and second tube sheets and separated from the first chamber by the first tube sheet, and a third chamber adjoining the second tube sheet and separated from the second chamber by the second tube sheet, and a fluid treatment element disposed in the second chamber and comprising a hollow pleated fluid treatment pack having first and second lengthwise end faces through which fluid can flow, a first lengthwise end connected to the first tube sheet, a tube communicating with a hollow center of the fluid treatment pack and connected to the second tube sheet, and a fluid impervious member surrounding the fluid treatment pack for preventing fluid from flowing into the fluid treatment pack from the second chamber except through the second lengthwise end face of the fluid treatment pack.
Fluid treatment assemblies may comprise a fluid treatment element having a hollow center and a pleated fluid treatment pack surrounding the hollow center, a blind end cap connected to a first lengthwise end of the fluid treatment pack, and an open end cap connected to a second lengthwise end of the fluid treatment pack, and a housing containing the fluid treatment element and including a first fluid port opening onto a region of the housing on an exterior of the fluid treatment element, a second fluid port opening onto a region of the housing on an exterior of the fluid treatment element, and a third fluid port communicating with the hollow center of the fluid treatment pack, the fluid treatment element being disposed between the first and second fluid ports, the housing surrounding the fluid treatment element sufficiently closely that a flow path between the first and second fluid ports passing through the fluid treatment pack provides lower resistance to flow than a flow path between the first and second fluid ports passing between the fluid treatment pack and the housing.
Fluid treatment elements may have first and second open ends through which fluid can flow and may comprise a pleated fluid treatment pack disposed between the open ends of the fluid treatment element and a fluid impervious member surrounding the fluid treatment pack and preventing fluid from flowing into the fluid treatment pack from an exterior thereof except in a lengthwise midportion of the fluid treatment element.
Fluid treatment methods may comprise introducing a process fluid into a cylindrical fluid treatment pack comprising a fluid treatment layer having a radially inner side and a radially outer side, passing the process fluid in a lengthwise direction of the fluid treatment pack along the radially inner side of the fluid treatment layer to produce a fluid shear force on the radially inner side of the fluid treatment layer, passing a portion of the process fluid though the fluid treatment layer to the radially outer side of the fluid treatment layer to form a permeate, and discharging the permeate and the process fluid which does not pass through the fluid treatment layer from the fluid treatment element.
Fluid treatment methods may comprise introducing a process fluid into a first mesh layer on a first side of a fluid treatment layer at a first lengthwise end of a fluid treatment element, passing the process fluid in a lengthwise direction of the fluid treatment pack within the first mesh layer toward a second lengthwise end of the fluid treatment element to generate a fluid shear force on the first side of the fluid treatment layer, and passing a portion of the process fluid through the fluid treatment layer into a second mesh layer on a second side of the fluid treatment layer.
Fluid treatment methods may comprise introducing a fluid through a lengthwise end face of a fluid treatment pack into a first mesh layer on a first side of a fluid treatment layer of the fluid treatment pack, and passing at least a portion of the fluid through the fluid treatment layer into a second mesh layer on a second side of the fluid treatment layer.
Fluid treatment methods may comprise introducing a process fluid into a fluid treatment clement having a fluid treatment layer and a drainage mesh disposed on one side of the fluid treatment layer, the drainage mesh having first and second sets of strands extending diagonally with respect to a lengthwise direction of the fluid treatment element, passing the process fluid through the drainage mesh in a lengthwise direction of the fluid treatment element to produce a fluid shear force along a surface of the fluid treatment layer, and passing a portion of the process fluid through the fluid treatment layer to form a permeate.
Fluid treatment methods may comprise introducing a -fluid into a first fluid treatment element at a fist lengthwise end thereof, passing a first portion of the fluid along a first flow path through a fluid treatment pack of the first fluid treatment element and passing a second portion of the fluid along a second flow path through the fluid treatment element bypassing the fluid treatment pack, combining fluid which has passed along the first and second flow paths at a second lengthwise end of the fluid treatment element, and discharging the combined fluid from the first fluid treatment element.
Fluid treatment methods may comprise passing a first fluid stream through a pleated fluid treatment element in a lengthwise direction of the fluid treatment element on a first side of a fluid treatment layer of the fluid treatment element, passing a second fluid stream through the fluid treatment element in a lengthwise direction of the fluid treatment element on a second side of the fluid treatment layer, and transferring material across the fluid treatment layer between the two fluid streams. The material transfer is carried out without direct mixing of the fluid streams.
Fluid treatment methods may comprise passing a fluid through a fluid treatment layer from a first side to a second side of the fluid treatment layer to treat the fluid, and then cleaning the fluid treatment layer by passing a liquid and a gas along the first side of the fluid treatment layer in a lengthwise direction of the fluid treatment element.
Fluid treatment methods comprise passing a fluid through a fluid treatment layer of a fluid treatment element in a first direction, passing a mixture of liquid and gas through the fluid treatment layer in a second direction to dislodge particles from the fluid treatment layer; and discharging the mixture of liquid and gas and the dislodged particles from the fluid treatment element.
Fluid treatment methods may comprise introducing a process fluid into a hollow center of a pleated fluid treatment element at a first lengthwise end of the fluid treatment element, passing the process fluid outward from the hollow center into a fluid treatment pack surrounding the hollow center, passing the process fluid within the fluid treatment pack in a lengthwise direction of the fluid treatment element along a first surface of a fluid treatment layer of the fluid treatment element, passing a portion of the process fluid through the fluid treatment layer, and discharging process fluid which does not pass through the fluid treatment layer from a second lengthwise end of the fluid treatment element.
Fluid treatment methods may comprise introducing a fluid to be treated into a fluid treatment element on a first side of a fluid treatment layer of the fluid treatment element, passing all of the fluid to be treated through the fluid treatment layer, introducing a cleaning fluid into the fluid treatment element on the first side of the fluid treatment layer, and cleaning the fluid treatment layer by passing the cleaning fluid along the fist side of the fluid treatment layer to generate a fluid shear force on the first side of the fluid treatment layer.
Fluid treatment methods may comprise introducing a fluid from a first chamber of a housing through a first tube sheet into a first lengthwise end of a pleated fluid treatment clement disposed in a second chamber of the housing separated from the first chamber by the first tube sheet, passing the fluid within the fluid treatment element along a radially outer side of a fluid treatment layer of the fluid treatment element in a lengthwise direction of the fluid treatment element to generate a fluid shear force on the radially outer side of the fluid treatment layer while retaining the fluid in the fluid treatment element by a fluid impervious member, and discharging the fluid radially outward from the fluid treatment element into the second chamber in the vicinity of a second lengthwise end of the fluid treatment element.
Fluid treatment methods may comprise introducing a fluid from a first chamber of a housing radially into a fluid treatment element disposed in the first chamber, passing the fluid within the fluid treatment element along a radially outer side of a fluid treatment layer of the fluid treatment element in a lengthwise direction of the fluid treatment element to generate a fluid shear force on the radially outer side of the fluid treatment layer while retaining the fluid in the fluid treatment element by a fluid impervious member, and discharging the fluid from a lengthwise end of the fluid treatment element through a first tube sheet into a second chamber of the housing separated from the first chamber by the first tube sheet.
Fluid treatment methods may comprise introducing a fluid to be treated into a pleated fluid treatment element, passing the fluid in a lengthwise direction of the fluid treatment element along a first side of a fluid treatment layer of the fluid treatment element toward a first lengthwise end of the fluid treatment element, passing a portion of the fluid through the fluid treatment layer, discharging the portion of the fluid which passed through the fluid treatment layer from a second lengthwise end of the fluid treatment element, and discharging fluid which did not pass through the fluid treatment layer from the first lengthwise end of the fluid treatment element.
The numerous advantages of the various above-mentioned and other aspects of the present invention will be described in detail below. Among these advantages are versatility permitting various modes of operation, high efficiency, effective use of space, and an increased lifespan of fluid treatment elements.
A fluid treatment element according to the present invention can be used to treat a wide variety of fluids, including gases, liquids, and multi-phase combinations, such as mixtures of gases and liquids, and it can be employed to perform a wide variety of fluid treatment processes, such as removal of particles from a fluid (particle filtration), coalescing, transfer of dissolved substances between two fluids, and concentration of a process fluid. Particles which may be removed from a fluid when the fluid treatment element is used for particle filtration may range in size from coarse particles (generally defined as particles about 0.1 mm in diameter and above) down to particles in the ionic range (generally defined as particles measuring about 10xe2x88x927 to about 10xe2x88x925 mm in diameter). Thus, the fluid treatment element may be used to perform filtration such as coarse particle filtration, fine particle filtration, microfiltration, ultrafiltration, reverse osmosis, gas permeation, dialysis, pervaporation, vapor permeation, membrane distillation, electrodialysis, electrofiltration, and liquid membranes.
A fluid treatment element according to the present invention may be a disposable element which is intended to be discarded when it becomes loaded with particles, or it can be a reusable element which can be cleaned upon becoming loaded, either while still installed in a housing or after being removed therefrom, to enable the element to be reused. In a number of preferred embodiments of the present invention, a fluid treatment element is capable of being cleaned while installed in a housing either by backwashing or by crossflow.
Fluid treatment assemblies may comprise a fluid treatment pack and a tube surrounding the fluid treatment pack. The tube may have openings at or in the vicinity of the lengthwise ends of the tube and a blind region without openings extending between the openings. The assembly may include end caps sealed to the ends of the filter pack.
An arrangement for contacting a liquid and a gas that is soluble in the liquid may comprise a fluid treatment device, a source of the gas, and a source of the liquid. A method for contacting a liquid and a gas may use the above arrangement. The method enables the preparation of solutions of gases in liquids that are free or substantially free of bubbles. An arrangement for degassifying a liquid containing a dissolved gas may comprise a fluid treatment device, a source of the liquid, and a difference in pressure between the first and second flow paths.
Fluid treatment methods may comprise introducing a process fluid into a pleated fluid treatment element; passing at least a portion of the process fluid through a fluid treatment medium of the element; and passing a gas which is different from the process fluid along the first side of the fluid treatment medium to remove particles from the first side of the fluid treatment medium.
Fluid treatment arrangements may comprise a pleated fluid treatment element; a housing containing the fluid treatment element and having a first fluid port communicating with the first lengthwise end and second and third fluid ports communicating with the second lengthwise end of the fluid treatment element, fluid being able to flow from the first port to the second and third ports through the fluid treatment element without passing through the fluid treatment medium; a source of liquid to be treated connected to one of the first and second fluid ports; and a source of crossflow cleaning gas connected to third fluid port.
Fluid treatment modules may comprise headers having bores for fluid communication, a casing, and a fluid treatment element. A fluid treatment assembly may comprise a plurality of fluid treatment modules.
Methods for cleaning a fluid treatment element may comprise a fluid treatment medium having a first side and a second side, the first side having particles deposited thereon. The method involves passing a cleaning gas along the first side of the fluid treatment medium without first passing through the fluid treatment medium.
Although the present invention will be described with respect to a number of embodiments, the present invention is not limited to the specific structures of those embodiments, and one or more features of one embodiment may be freely combined with one of more features of another embodiment without departing from the scope of the present invention.